Two-dimensional calculation model is not sufficient for accurately calculating electric field distribution around a building under EHV transmission lines because of intricate space between building and transmission lines. Considering the factors such as span and sag

the authors establish a three-dimensional calculation model based on the charge simulation method to precisely describe the relative position between building and transmission lines. A line charge unit model is used to calculate three-dimensional electric field around a building under transmission lines. Simulation results show that: the electric field is of greater intensity above the building than in other areas

and appears obvious distortion compared with the situation without any building; and increasing the radius of curvature of building edges can improve the electromagnetic environment around a building.